A great many tractors used by farmers and others may be used with either two back driving wheels, one on each side, or four back driving wheels, two on either side aligned on a common axis. The two additional back wheels, usually referred to as dual wheels, provide a much greater support surface for the tractor, distributing the load over twice as much surface area. They also serve to distribute the driving force over such greater surface area.
Dual wheels are particularly helpful for certain types of operations, including operations in muddy soil and the like. However, dual wheels can hinder other tractor operations, particularly since they make the overall width of the tractor much greater, which tends to limit tractor maneuverability. Therefore, particularly for large farm tractors performing a number of different functions, it is considered desirable to have a single tractor adaptable for use either with or without dual wheels, as needed by the task at hand.
This requires an ability to mount and remove dual wheels frequently and easily. However, removal of dual wheels, particularly so-called "spacer duals," has been anything but easy. As a result, tractors are often used with dual wheels when they are not needed or without dual wheels when they may be helpful.
Spacer duals for tractors typically have a dual-wheel rim extension which is sized to engage, usually in telescoping fashion, the rim of the adjacent main wheel. The dual wheel is held in position against such main wheel by the use of a number of connecting links, such as J-bolts (usually 4-8), which extend between eyelet members on the rim of the main wheel and corresponding aligned apertures usually formed on tabs extending inwardly from the inside surface of the dual-wheel rim. When the dual wheel is mounted, such J-bolts are tightened to hold the wheel in place. Typically, they are tightened once or twice until there is firm engagement between the dual-wheel rim extension and the rim of the adjacent main wheel.
Even after a fairly limited amount of use of the tractor with the dual wheels in place, an extremely tight frictional engagement develops between the dual-wheel rim extension and the main-wheel rim. For the many farmers and others who use tractors with dual wheels, dual wheel removal is a major problem. While removal of the J-bolts is obviously an easy procedure, after removal J-bolt removal the dual-wheel rim extension remains in tight frictional engagement with the rim of the adjacent main wheel, until somehow or other this engagement is broken.
A variety of different methods have been used to break such frictional engagement. Some farmers use jacks of various kinds in make-shift operations which are time-consuming and difficult. Others will bang away with hammers, two-by-fours, and other implements, sometimes over extended periods, until such frictional engagement is broken. Still others have been known to simply continue using their tractors with the connecting links removed until the frictional engagement eventually breaks and the dual wheels fall off.
Various devices have been used in the past in different sorts of wheel pulling operations, including devices specifically intended for moving of large tractor wheels. Such devices are often complex in construction. Such devices typically apply force to a central point such as the axle, and in many cases have symmetrical application of force with respect to the wheel. Complex procedures are often required for set-up and use, and removal operations with such devices are often time-consuming.
There remains a need for a simple, inexpensive device for removal of tractor dual wheels which can carry out the dual wheel removal operation quickly and without difficulty.